I really like the looks of 20" rims on the g35 coupe... I plan on lowering the car as well. Is there anything i should be concerned about with this size wheel? Any info good and bad would be awesome. Sorry if this has been asked several times but i couldn't find the information while searching, if you know of a thread that has this info please advise me. Thanks everyone.

 

Ride comfort, performance.

 

Thinner the side wall, worse the ride. Bigger/Heavier the wheel, slower acceleration.





But, they DO look nice.

 

So i did some more searching and found a pretty decent thread with this information....

A larger wheel and tire package can actually decrease maneuverability and will increase braking distances. Your gas mileage and acceleration times will definitely suffer. Trend-based thinking is that, by dropping the sidewall height of the tire and increasing the diameter of a wheel, an improvement in steering response and lateral handling can be found. While this is true to a certain extent, there is a point of diminishing returns.

In theory, an improvement in handling comes with an up-sized wheel and tire package. Decreasing the tire aspect ratio, or the percentage of tire width to tire height, also decreases side-to-side tire flex. While crisper handling is possible with a shorter tire, the pneumatic cushion between the road and car is less effective. The difference can be as dramatic as dozing off on an overstuffed mattress or trying to get cozy with a 1/2-inch thick foam camping pad.

Increased mass of larger wheels causes other problems. The body of the vehicle sitting atop the suspension is sprung weight. The wheels and tires are bolted to the ends of the suspension are unsprung weight. Anyone who remembers playing with a gyroscope as a kid can recall how difficult the toys were to tilt or move around once they got spinning. Unsprung weight like 20inch wheels can overwhelm the ability of a suspension to maintain vehicle control.

Big wheels want to keep on turning. Added rotating mass of bigger wheels can overwhelm brakes designed for smaller diameter and usually lighter wheels. I am starting to read and hear of more and more suspension part and wheel bearing failures in the G35/350z cars with larger than factory sized wheels. Engineers submit a vehicle to long hours of development and testing to determine the best wheel and tire combination. Suspension and brake system are designed for the wheels and tires the factory bolts on. Anything else is style-based guesswork and will hurt the performance of the car.


Okay so after reading this, what i don't understand is the fact that this person didn't take into consideration that there are some light weight 20's out there, and are you seriously going to be able to feel that much of a difference in performance from 18-19-20? and how much could your gas mileage really decrease, it seems like this comment is a little over the top...

What are average weights for 18, 19 and 20 inch rims?

 

I had 20s and down size to 19s. 20s have that WOW factor but man they were like boat anchors. Stopping suck accelerating suck + you cant go as low as if you were on 19s or 18s body wise. I am so happy with the 19s car feels so much better now to drive shaved off 30lbs rotation mass by going to 19s. I would not go back.

 

Rastaman,

How much did your 20's weigh?

 

the fronts were 62lbs with tires each
rears were 67lbs with tires each

 

I had the "sport" 18" OEM wheels when I bought the car. I went with 19" and you still get that "wow" factor, but I kept the EXACT same rolling circumference (buy using 245 40 19's vs OEM size of 235 50 18"s) so my speedo didn't change and the handling is superb.